Switch mechanism and follow-up system



Feb. 26, 1946; J. o. YElDA 2,395,604

SWITCH MECHANISM AND FOLLOW-UP SYSTEM- Filed April 23, 1942 I 2 Sheets-Sheet 1 'Feb. 26,1946. v -J. o. YEIDA 2,395,604

SWITCH MECHANISM AND FOLLOW-UP SYSTEM Filed April 25, 1942 2 Sheets-Sheet 2' Patented Feb. 26, 1946 SWITCH MECHANISM AND FOLLOW-UP SYSTEM John 0. Yeida, Herculaneum, Mo., assignor to Automatic Control Corporation, St. Louis, Mo., a corporation of Delaware Application April 23, 1942, Serial No. 440,193

4 Claims.

The present invention relates to a switch mechanism and follow-up system.

Generally speaking, this invention comprises a switch that applies to a single-operating part the movement of two separate power or motion sources. For instance, when used with a followup motor system, the switch may embody a switch lever, means to apply to the lever the controlling force, such as that produced by a thermostat, and means to apply to the switch lever the movement produced bythe motor itself.

Among the objects of the invention is the provision of a switch that will accomplish the fore going results. More particularly, the objects are to provide a device including a convenient, adjustable, temperature-responsive means, a switch, and transmission mechanism between the temperature-responsive means and the switch, together with additional power means interposing an additional movement upon the transmission means, that is carried to the switch.

Specifically, it is an object of the invention to provide a switch lever, adapted to pivot about a fixed point, and two power means, with an interposed system of levers to transmit movements produced by each power means to the lever in such wise that movements of one power means can override and counteract movements produced by the other.

In the drawings:

Fig. 1 is a side elevation of the mechanism constructed in accordance with the invention;

Fig. 2 is a front elevation thereof;

Fig. 3 is a vertical medial section taken on the line 3-3 of Fig. 2;

Fig. 4 is a vertical section taken near the front of the switch on the line 44 of Fig. '3;

Fig. 5 is a horizontal section on the line 5-5 on the bottom of Fig. 3; and

Fig. 6 is a diagrammatic view showing one combination in which the switch may be used.

Broadly, the mechanism comprises a, switch 10, a thermostatic power unit II, and a second power device 12. In this description, the power device l2 will generally be referred to as a follow-up mechanism, although it is not intended that the expression shall be other than illustrative. J

The thermostatic unit H comprises a bulb I4, a capillary tube l5, and an expansible member generally indicated at IS. The expansible member comprises an outer relatively rigid cupshaped member I! with an inner relatively flexible cup-shaped member IS, the two being secured together toward the open part of their side walls, and providing an expansion chamber between them into which the capillary l5 communicates. The member I! is connectedto the switch housing.

, The switch member includes a front plate 20 to which is secured a channel-shaped member 2|, forming sidev and back walls complementary to the front wall formed by the panel 20. The back wall of the member 2| has an opening receiving a stud 23, spring pressed against the diaphragm member l8 by a spring 24, acting between a washer 25 fixed to the stud 23 and an additional washer 26 adjacent the member 2|. The stud 23 is held against rotation by a pin 21 extending through the stud and out through slots 28 in the member 2| that permits axial movement of the stud but prevents rotation thereof.

The outer end of the stud is threaded to receive a sleeve member 30 with a self centering washer at the inner end thereof. The sleeve is provided with a dial 3| registering with a pointer 32. The sleeve has also a tubular portion 33 adjacent the end of the stud with complementary holes through which a cotter key 34 may be passed to fix the relative adjustment of the sleeve 30 upon the stud 23.

The sleeve 30, as will beobserved, passes through a suitable opening in the front panel 20. The pointer 32 is part of a wearing plate 35 on the front of the panel 20. v

A primary lever 40 has a pivot 4| at its upper end. Intermediate its ends, it has an opening through which the stud 23 passes, and adjacent the opening the primary lever 40 has upstruck portions 42 that are caused to engage the self centering washer that forms a part of the sleeve 30.

At its lower end, the primary lever 40 is connected by a spring blade 43 with a secondary lever 44. The secondary lever 44 is pivoted at 45 to the member 2|. A spring 46 acts between the wearing plate 35 and the secondary lever 44 to urge the same in a clockwise direction with the mechanism in the position of Fig. 3. Such clockwise displacement of the secondary lever draws the spring blade 43 to the right in Fig. 3, and, consequently, draws the primary lever 40 counterclockwise about its pivot 4| the maximum distance permitted by the sleeve 30 which restricts the primary lever by contact of the portions 42 thereon.

At its outer end, the secondary lever 44 has a double switch contact 50. This contact 50 is mounted upon a conducting piece 5| (Fig. 4) projecting from an insulating block.52 secured across bifurcations formed. on the lower end of the secondary lever 44.

The contact 50 is connected by a flexible lead '54 with a U-shaped terminal 55 projecting through to the outside of the front panel 20.

The contact 50 engages alternatively with relatively fixed contacts 60 and BI, The contact 60 is formed upon a bracket 62 riveted to the front panel and provided with a terminal 63 projecting through that panel.

The contact BI is formed on a screw threaded into a U-shaped bracket 64 (Figs. 3 and 5), so as to be spaced opposite the contact 60. The bracket 64 has a terminal 65 projecting from one of its legs through its front panel 20.

From the foregoing, it may be seen that operation of the primar lever can shift the contact 50 so that it closes with either the contact 60 or the contact 6|. Also the contact 6| is adjustable toward and from the contact 60.

A means in addition to the thermostat l l is provided for displacing the primary lever, As has heretofore been stated, the primary lever is pivoted at 4|. The pivot 4|, however, is not secured to the switch housing, but is supported upon projecting ears on a supporting or followup lever 10. The lever I0 itself is pivoted at H to the housing member 2|, the pivot 7| passing through an enlarged opening in the primary lever 40. The lever 10 is, in the main, formed of two side sections joined at their ends with the primary lever operating in the opening within the followup lever and with the stud 23 likewise operating in that opening. A coil spring 69 operating between the wearing plate and the lever 10 urges the latter to its maximum counterclockwise posi tion in Fig. 3,

At its lower end, the follow-up lever is provided with a cross member 12 having an upturned flange 13 thereon for stiffening purposes, and having an opening therethrough astride a shaft 14. The connecting portion of the followup lever 19 has upstruck portions 15 thereon on each side of the shaft 14, these being adapted to engage with a sleeve 16 threaded onto the shaft.

This sleeve is block-shaped and has a pin 18 projecting therefrom and engaging a slot I9 in the casing member 2| by means of which the sleeve I6 may move axiall but not rotatably relative to the shaft 14.

The shaft 14 passes through the casing 2| and is supported in a sleeve 80 secured to the member 2|. A flange 8| on the shaft 14 engages a spring washer 82 and this cooperates with a nut 83 and washers 84 at the other end of the shaft H to secure a tight fit free of lost motion. The operating member l2 has a flattened opening engaging over the flattened end of the shaft held thereon by a nut 85.

It can be seen that rotation of the shaft 74 axiall displaces the sleeve 16 in one direction or the other, dependent upon the direction of rotation of the arm l2, Since the spring 69 con stantl urges the follow-up lever 10 to its maximum counterclockwise position about the pivot "H, the follow-up lever will follow the sleeve 16 with consequent displacement of the pivot 4|, about which the primary lever 40 operates.

As a typical use, reference is made to Fig. 6. In Fig. 6, there is shown a motor M having a for ward winding and a reverse winding, The motor is connected to a power line 90, and upon the motor are two terminal posts F and R, the F being for the forward winding and the R being for the reverse winding. The terminal F is connected by a lead 9| to the contact Bl. The R terminal is connected by a line 92 to the contact 80. The contact 50 is connected to a line 93 which is the other power line.

The motor, through a gear train 94, operates a crank 95 that may be turned through any suitable distance, here about during the operation of the device. The crank is connected b a link 96 to the arm I2. It is also connected by a linkage generally indicated at 81 to a louvre 9B controlling the flow of air to the motor, such as an aircraft motor.

Operat on The switch itself operates basically in response to change in temperature at the bulb I 4, This bulb is located at a suitable place, the temperature of which is to be controlled. Assume a starting or neutral position in which the contact '50 is spaced from both the contact 60 and the contact 6|. In case of a rise in temperature, the diaphragm I 8 will move to the right in Fig. 3, displacing the stud 23 in the same direction against the force of the spring 24, and carrying with it the sleeve 30. In this case, the primary lever 40 will be permitted to pivot counterclockwise about the pivot 4|, The spring 46 acting upon the secondary lever constantly urges the secondary lever to pivot clockwise about the pivot 45. In the neutral position, an movement was prohibited by the connection between the secondary lever and the primar lever and the limiting of displacement of the primary lever by its engagement against the sleeve 30. Hence, the displacement of the sleeve 30 upon increase in temperature permits some clockwise pivoting of the secondary lever, the amount being determined by the amount of temperature increase. This thereupon causes the contact 50 to close with the contact 6|.

Likewise, upon subsequent reduction of temperature about the bulb H, the diaphragm I 8 will move to the left in Fig. 3, and the heavy spring 24 will cause the stud 23 to follow this leftward movement, drawing the sleeve 30 with it. This controlling force displaces the primary lever 40 about its pivot 4|, and through the connection 43 which effectively draws the secondary lever, which thereupon pivots counterclockwise against the spring 46 until the contact 50 leaves the contact 6| and, if the temperature drop is sufficient, engages the contact 60.

The shaft 14 represents a power means providing forward movement of the end of the followup lever 10. If the sleeve 16 is displaced toward the right in Fig. 3 by movement of the shaft (4, the spring 69 will cause the follow-up lever 10 to pivot counterclockwise about its pivot H, so as to remain in engagement with the sleeve 16. This action displaces the pivot 4| bodily to the left in Fig. 3. Such displacement of the pivot 4| displaces the upper end of the primary lever 40 and tends to remove the primary lever from the sleeve 30, which sleeve is in a position determined by the temperature. However, the primary lever is not permitted to withdraw from the sleeve because the spring 46 acting upon the secondary lever pivots the same to draw the primary lever in a direction to contact the sleeve. Manifestly, such displacement of the secondary lever causes closure of the contacts 50 and BI.

Upon subsequent reversal of the direction of movement of the shaft 14 and, consequent displacement of the sleeve 16 to the left in Fig. 3, the follow-up lever 10 pivots clockwise about the pivot H. This displaces the pivot 4| to the right and efiects a positive pivoting of the primary lever 40 about the engagement of the portions 42 and the sleeve 30, and also pivoting of the secondary lever 44 about the pivot 45 against the force of the spring 46. This will separate the contacts 50 and BI and may close the contacts 50 and 60.

It will be seen that in this switch the path of travel of the contact 50 relative to the contacts 60 and BI remains unchanged. The primary lever 40 integrates movement of the thermostat and the shaft I4 and applies such integrated movement to the secondary lever through the resilient connection 43. Thus, although the primary lever 40 may move in a path that is not fixed, the contact 5|] is restricted to the fixed path of arcuate movement about the pivot 45.

The force of the spring 46 acting through its lever arm is not enough to effect a displacement of the follow-up lever against the action of the spring 69 should the sleeve 30 be displaced beyond a point where movement of the secondary lever can occur to move the primary lever and thereby cause it to remain in contact.

Fig. 6 shows an application of this switch. Upon a rise in temperature within a motor housing, the bulb [4 will heat, effecting a displacement of the primary lever 40 and the secondary lever 44 to bring the contact 50 against the contact 6|. This closes the forward circuit for the motor M. This motor operates through its gearing 94 to shift the crank 95 which opens the louvre 98 to admit more air tothe motor. At the same time, it displaces the link 96 connected with the arm l2 and causes movement of the sleeve 16 toward the back of the switch, which is downwardly in I Fig. 6, and to the left in Fig. 3. This movement displaces the follow-up lever HI clockwise about its pivot H causing a displacement of the pivot 4| to the right in Fig. 3, and upwardly in Fig. 6.

The primary lever 49 is thus pivoted clockwise about the sleeve 30 and through the connection also pivots the secondary lever 44 counterclockwise about the pivot 45 to reopen the contacts 50 and 6|. Thereupon the motor stops with the louvre in a position suitable 'for that temperature of the motor. If the motor continues to get hotter, the contact 50 will again close with the contact GI and remain closed until the louvre is opened further and the contacts are again separated by the follow-up mechanism.

It is obvious how a cooling of the bulb M will close the reverse winding by engagement of the contacts 50 and 60, which remain closed until the louvre closes to a point suitable for that temperature of the motor.

In the foregoing description, it was not intended to indicate that the switch was limited to use in the position of Fig. 3, when reference was made to the right side of the switch, or the left side of the bottom or the top.

What is claimed is 1. In a switch mechanism for use in controlling a motor, a housing, a first power means adapted to produce reciprocal movement, an abutment member moved by said first power means, a second power means having an abutment element spaced from the abutment member, said second power means being adapted to be operated by the operation of the motor to produce reciprocal movements of said abutment element, a followup lever pivoted to the housing and extending adjacent the abutment element to be engaged therewith, a primary lever pivoted to the followup lever and having oscillating engagement with the abutment member of the first power means, switch means moved by the primary lever, spring means urging the follow-up lever into engagement with the abutment element of the second power means and to urge the pivot of the primary lever in one direction of movement, and additional spring means urging the primary lever into engagement with the abutment member of the first power means.

2. In a switch mechanism for use in controlling a motor, a housing, a first power means adapted to produce reciprocal movement, an abutment member moved by said first power means, a second power means having an abutment element spaced from the abutment member, said second power means being adapted to be operated by the operation of the motor to produce reciprocal movements of said abutment element, a followup lever pivoted to the housing and extending adjacent the abutment element to be engaged therewith, a primary lever pivoted to the followup lever and having oscillating engagement with the abutment member of the first power means, switch means moved by the primary lever, said switch means comprising a switch lever and contact means, the switch lever being pivoted to the housing and to the primary lever, spring means acting on the switch lever to urge it in one direction and to urge the primary lever to pivot in one direction about its abutment with the abutment member, and spring means acting on the followup lever to urge it to pivot against the abutment member to urge its pivot with the primary lever in one direction of movement to a limit determined by the position of the abutment element of the second power means.

3. In a switch mechanism for use in controlling a reversible motor, a housing, a first power means having a reciprocable member mounted on the housing for, movement back and forth, an abutment member on said reciprocable member, a second power means having an abutment element within the housing and adapted, to be moved back i and forth upon operation of the motor, a follow-up lever pivoted to the housing and extending across the abutment element of the second power means, spring means urging said follow-up lever to rock about its pivot to maintain the lever in contact with the abutment element, a primary lever, pivoted to the follow-up lever and extending against the abutment member of the first power means, and rockable on said abutment member, said primary lever being pivoted about the follow-up lever when the first power means moves the abutment member, and being pivoted about the abutment member when the follow-up lever rocks by movement of the second power means, switch means includinga pair of opposite fixed contacts mounted on the housing and a movable contact displaced by the primary lever into engagement with one or the other of them, said fixed contacts being adaptedfor connection with the motor to cause it to operate in opposite directions, the

' second power means being adapted, upon operation of the motor, to shift the follow-up lever and the primary lever to reseparate the movable contact from the fixed contact.

4. In a switch mechanism, a housing having a front panel and a back panel, a thermostatic means having a first reciprocating stud extending through the back panel, an abutment member on the stud, a second power operated stud extending through the back panel and having an abutment element thereon moved toward and from the the face thereof toward the back panel, a switch lever pivotally mounted on the housing and pivotally connected with the primary lever, the switch lever having a movable contact, opposed fixed contacts engageable selectively by the movable contact, and spring means urging the primary lever to rock about its pivot on the followup lever into engagement with the abutment member.

JOHN O. YEIDA. 

